package multireactor;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;

/**
 * @author fangkun
 * @create 2022-06-02-16:54
 */
public class AsyncHandler implements Runnable{

    private SocketChannel channel;
    private SelectionKey sk;
    StringBuilder stringBuilder = new StringBuilder();

    ByteBuffer inputBuffer = ByteBuffer.allocate(1024);
    ByteBuffer outputBuffer = ByteBuffer.allocate(1024);

    public AsyncHandler(SocketChannel channel) {
        this.channel = channel;
    }

    public SocketChannel getChannel() {
        return channel;
    }

    public SelectionKey getSk() {
        return sk;
    }

    public void setSk(SelectionKey sk) {
        this.sk = sk;
    }

    @Override
    public void run() {
        try {

            if (sk.isReadable()){
                read();
            }else if (sk.isWritable()){
                write();
            }

        } catch (Exception e){

        }
    }

    private void write() throws IOException {
        int write=-1;
        outputBuffer.flip();
        if(outputBuffer.hasRemaining()){
            write=channel.write(outputBuffer); //把收到的数据写回到客户端
        }
        outputBuffer.clear();
        stringBuilder.delete(0,stringBuilder.length());
        if(write<=0){
            this.sk.channel().close();
        }else{
            channel.write(ByteBuffer.wrap("\r\nreactor> ".getBytes()));
            this.sk.interestOps(SelectionKey.OP_READ);//又转化为读事件
        }
    }


    private void read() throws IOException {
        inputBuffer.clear();
        int n = channel.read(inputBuffer);
        if (inputBufferComplete(n)){
            System.out.println(Thread.currentThread().getName()+": Server端收到客户端的请求消息："+stringBuilder.toString());

            outputBuffer.put(stringBuilder.toString().getBytes(StandardCharsets.UTF_8));
            this.sk.interestOps(SelectionKey.OP_READ);
        }

    }

    private boolean inputBufferComplete(int bytes) throws EOFException {
        if (bytes > 0){

            inputBuffer.flip();
            while (inputBuffer.hasRemaining()){
                byte ch = inputBuffer.get();
                if (ch == 3){
                    throw new EOFException();
                }else if (ch=='\r'||ch=='\n'){
                    return true;
                }else {
                    stringBuilder.append((char)ch);
                }
            }
        }else if (bytes ==1){
            throw new EOFException();
        }
        return false;
    }
}












